Web/JavaScript/Reference/Global objects/String/fromCodePoint

The static String.fromCodePoint() method returns a string created by using the specified sequence of code points.

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Syntax

String.fromCodePoint(num1[, ...[, numN]])

Parameters

num1, ..., numN

A sequence of code points.

Return value

A string created by using the specified sequence of code points.

Exceptions

• A RangeError is thrown if an invalid Unicode code point is given (e.g. "RangeError: NaN is not a valid code point").

Description

This method returns a string (and not a String object).

Because fromCodePoint() is a static method of String, you must call it as String.fromCodePoint(), rather than as a method of a String object you created.

Polyfill

The String.fromCodePoint() method has been added to ECMAScript 2015 and may not be supported in all web browsers or environments yet.

Use the code below for a polyfill:

if (!String.fromCodePoint) (function(stringFromCharCode) {
    var fromCodePoint = function(_) {
      var codeUnits = [], codeLen = 0, result = "";
      for (var index=0, len = arguments.length; index !== len; ++index) {
        var codePoint = +arguments[index];
        // correctly handles all cases including `NaN`, `-Infinity`, `+Infinity`
        // The surrounding `!(...)` is required to correctly handle `NaN` cases
        // The (codePoint>>>0) === codePoint clause handles decimals and negatives
        if (!(codePoint < 0x10FFFF && (codePoint>>>0) === codePoint))
          throw RangeError("Invalid code point: " + codePoint);
        if (codePoint <= 0xFFFF) { // BMP code point
          codeLen = codeUnits.push(codePoint);
        } else { // Astral code point; split in surrogate halves
          // https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
          codePoint -= 0x10000;
          codeLen = codeUnits.push(
            (codePoint >> 10) + 0xD800,  // highSurrogate
            (codePoint % 0x400) + 0xDC00 // lowSurrogate
          );
        }
        if (codeLen >= 0x3fff) {
          result += stringFromCharCode.apply(null, codeUnits);
          codeUnits.length = 0;
        }
      }
      return result + stringFromCharCode.apply(null, codeUnits);
    };
    try { // IE 8 only supports `Object.defineProperty` on DOM elements
      Object.defineProperty(String, "fromCodePoint", {
        "value": fromCodePoint, "configurable": true, "writable": true
      });
    } catch(e) {
      String.fromCodePoint = fromCodePoint;
    }
}(String.fromCharCode));

Examples

Using fromCodePoint()

Valid input:

String.fromCodePoint(42);       // "*"
String.fromCodePoint(65, 90);   // "AZ"
String.fromCodePoint(0x404);    // "\u0404" == "Є"
String.fromCodePoint(0x2F804);  // "\uD87E\uDC04"
String.fromCodePoint(194564);   // "\uD87E\uDC04"
String.fromCodePoint(0x1D306, 0x61, 0x1D307); // "\uD834\uDF06a\uD834\uDF07"

Invalid input:

String.fromCodePoint('_');      // RangeError
String.fromCodePoint(Infinity); // RangeError
String.fromCodePoint(-1);       // RangeError
String.fromCodePoint(3.14);     // RangeError
String.fromCodePoint(3e-2);     // RangeError
String.fromCodePoint(NaN);      // RangeError

Compared to fromCharCode()

String.fromCharCode() cannot return supplementary characters (i.e. code points 0x010000 – 0x10FFFF) by specifying their code point. Instead, it requires the UTF-16 surrogate pair in order to return a supplementary character:

String.fromCharCode(0xD83C, 0xDF03); // Code Point U+1F303 "Night with
String.fromCharCode(55356, 57091);   // Stars" == "\uD83C\uDF03"

String.fromCodePoint(), on the other hand, can return 4-byte supplementary characters, as well as the more common 2-byte BMP characters, by specifying their code point (which is equivalent to the UTF-32 code unit):

String.fromCodePoint(0x1F303); // or 127747 in decimal

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'String.fromCodePoint' in that specification.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
fromCodePoint	Chrome Full support 41	Edge Full support 12	Firefox Full support 29	IE No support No	Opera Full support 28	Safari Full support 10	WebView Android Full support 41	Chrome Android Full support 41	Firefox Android Full support 29	Opera Android Full support 28	Safari iOS Full support 10	Samsung Internet Android Full support 4.0	nodejs Full support 4.0.0 Full support 4.0.0 Full support 0.12 Disabled' Disabled' From version 0.12: this feature is behind the --harmony runtime flag.

Legend

Full support  

Full support

No support  

No support

User must explicitly enable this feature.'

User must explicitly enable this feature.

See also

• String.fromCharCode()
• String.prototype.charAt()
• String.prototype.codePointAt()
• String.prototype.charCodeAt()

String.fromCodePoint() by Mozilla Contributors is licensed under CC-BY-SA 2.5.